J/A+A/369/758 VRI photometry of BL Lac (1997-1999) (Fan+, 2001)
Optical observations of BL Lacertae from 1997 to 1999
Fan J.H., Qian B.C., Tao J.
<Astron. Astrophys. 369, 758 (2001)>
=2001A&A...369..758F 2001A&A...369..758F
ADC_Keywords: BL Lac objects ; Photometry, VRI
Keywords: galaxies: active - galaxies: photometry -
BL Lacertae objects: individual: BL Lac (PKS 2200+420)
Abstract:
We present the optical (V, R, and I) photometry for BL Lacertae, which
was observed from 1997 through 1999, with the 1.56-m telescope at the
Shanghai astronomical observatory (SHAO). After the 1997 outburst, it
dimmed to a low state and then brightened again. During the period
JD 2450701 to JD 2450701.5, variations of 0.40mag, 0.27mag, and
0.21mag over a time scale of 100min were found for V, R, and I bands,
suggesting that the variations were decreasing with wavelength. The
correlation between V, R, and I is also analyzed using the DCF
(Discrete Correlation Function) method. This shows that the
variability in the V, R, and I bands are correlated with no time delay
longer than 0.2day.
Objects:
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RA (2000) DE Designation(s)
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22 02 43.3 +42 16 40 BL Lac = PKS 2200+420
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 50 369 Optical measurements of BL Lacertae in 1997-1999
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See also:
J/A+AS/143/357 : Tuorla Quasar Monitoring (Katajainen+ 2000)
J/A+AS/136/455 : BVRI photometry of 3 BL Lac objects (Bai+, 1999)
J/A+AS/120/89 : 408MHz observations (Bondi+ 1996)
J/AZh/71/717 : Polarimetric Observations of BL Lac (Gagen-Torn+ 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian date
14- 18 F5.2 mag Vmag ? V magnitude
20- 24 F5.3 mag e_Vmag ? rms uncertainty in Vmag
26- 30 F5.2 mag Rmag ? R magnitude
32- 36 F5.3 mag e_Rmag ? rms uncertainty in Rmag
38- 42 F5.2 mag Imag ? I magnitude
44- 48 F5.3 mag e_Imag ? rms uncertainty in Imag
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Acknowledgements: Junhui Fan
(End) Patricia Bauer [CDS] 12-Apr-2001